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[kitz]

Glossary and Explanation of some of the common terms in use on this site.


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[kitz]

AAL5 - ATM Adaption Layer 5 [ITU.I363-5.1996]

ACK - Acknowledgement.  Control code used to indicate receipt of data from a remote computer.

ADSL - Asymmetric Digital Subscriber Line

AFAIK - As Far As I Know

ATM - Asynchronous Transfer Mode - More info on the ATM Backhaul & ATM packets.

Attenuation - A measurement indicating the reduction of signal strength.  In relation to adsl this figure may also be referred to as loop loss and give an approximate indication of the length of your line.  More info from ~ What is attenuation.

ATU-C - ADSL Transmission Unit - Central.  The adsl device in the local  exchange. eg DSLAM or MSAN.

ATU-R - ADSL Transmission Unit - Remote.  The adsl in the home/office. eg adsl modem or router.

AUP - Acceptable Usage Policy.  Terms laid out by your ISP defining acceptable use of your connection.

[kitz]

bps - bits per second. Used to indicate a measurement of speed.  Denoted by a small b

Bps - Bytes per second. Measurement of data transfer speed.  There are 8 bits in a Byte.  Denoted by a capital B and may also be displayed as B/Sec.

BER - Bit Error Rate.

bit - Binary Digit.

BPL - Broadband over Power Lines.

bRAS - Broadband Remote Access Server - A piece of hardware at a remote location, although collectively it may be used to describe a location of many Remote Access Servers and an important location from where your adsl is configured.  More information RAS.

bRAS profile - Broadband Remote Access Server Profile.  Profile information about your line, detailed information about bRAS and IP profile.

BSoD - Blue Screen of Death.

BT - Block Terminal.  Small box often installed in the home to join telephone wires.

BT - British Telecom.  UK's major telephone network supplier.  Split into several distinct sections. More info about the BT Groups.

BTo - British Telecom Openreach division.  - Responsible for the telephone access network and its maintenance,  such as your telephone line from the home to the exchange.

BTr - British Telecom Retail division - Seller of BT services to the general public.  Who we pay our telephone bill to. BT Internet/ BT Broadband also come under the BT retail division.

BTw - British Telecom Wholesale division - Provides network services to telecommunication companies such as our ISP.  BT adsl equipment is maintained & provided by BT Wholesale and they are responsible for such things like the DSLAM in the exchange, the RAS, and the BT backhaul to ISPs.

BTDT(GTS) - Been There Done That (Got the T Shirt)

BTW - By The Way.

Byte - 8 bits.

[kitz]

CBC - Capacity Based Charging.  BT wholesale method of charging ISPs based on the amount of capacity of their Central Pipes - More information CBC

CGI - Common Gateway Interface.  A webserver interface allowing the transfer of data between the webserver and remote computer.  CGI scripts allow dynamic interaction between a user and the server.

CGI - Computer Generated Imagery.

CHAP - Challenge Handshake Authentication Protocol. A protocol used on servers to validate the identity of remote clients. Commonly used by ISPs to validate customers logging on to the service.

CLI - Command Line Interface. - A method which allows interaction with a computer (or routers) operating system by issuing certain commands.

CLI - Caller Line Identification - Facility which allows customers to see who is calling before they answer the phone.

Colossus - BTw's Main Internet Backbone.  More info on Colossus IP Network.

CP - Consumer Products - BT speak for products sold to the general public.

CPA - Call Routing Apparatus (BT).

CPE - Customer Premises Equipment - BT speak for equipment in your home such as your router or telephone device.

CPU - Central Processing Unit - Computer hardware which carries out the data processing.

CRC - Cyclic Redundancy Check. 

CRC Error - Cyclic Redundancy Check Error - In relation to adsl, when your router has detected an error or lost packet.   More information CRC.

CSC - Customer Support (or Service) Centre for an ISP.

CSE - Customer Service Engineer.

CVLAN - Customer Virtual LAN.

CWDM - Coarse Wavelength Division Multiplexing.

CWSS - Copper Wideband Serving Section (BT).

[kitz]

DAC - Digital To Analog Converter.

DACS - Digital Access Carrier Systems. - ADSL will not work on DACed lines.

Data Rate - An indication of your throughput (or real) speed.

DataStream - Type of adsl where the ISP rents VP bandwidth at the local exchange from BT Wholesale.  For more info see Datastream

DCoE - Diagnostic Centre of Excellence. An Openreach resource, available to Field Technicians and other members of staff.

DECT -  Digital Enhanced Cordless Telecommunications

DHCP - Dynamic Host Configuration Protocol.  Method of automatically assigning IP addresses to network equipment.

DMT - Discrete Multi Tone Technology.  A method of converting digital data into frequencies that can be carried over the telephone line.  More info on DMT.

DLM - Dynamic Line Management.  BT Wholesale's method of managing ADSL profiles.  Detailed information on BTw's DLM system. Other LLU providers may have their own DLM system.

DNS - Domain Name System.  A method of converting human readable domain names into an IP address that can be understood by a computer. eg converting a web url such as bbc.co.uk into the IP address of the server where the website is held.

DNS - Domain Name Server.  A server which holds a list of DNS names to IP addresses.

DoS - Denial of Service.

DOS - Disk Operating System.

DP - Distribution Point. (BT)

DPI - Dots Per Inch.

DSL - Digital Subscriber Line - Broadband technology over the local telephone network.

DSLAM - Digital Subscriber Line Access Multiplexer.  Equipment usually at the local telephone exchange responsible for maintaining your adsl connection.
For detailed information see - DSLAM.

DSLMax - BT Wholesale's offering of 'up to 8Mbps' speeds.  More information : What is DSL Max and How Max DSL works

D/W - Drop Wire (BT).

DWDM - Dense Wavelength Division Multiplexing.

[roseway]

EDO - Extended Data Out. A type of random access memory (RAM).

EEPROM - Electronically-Erasable Programmable Read-Only Memory - A type of non-volatile memory used for storing small quantities of data, which will not be lost when the power is removed. For larger quantities of data, flash memory is used.

EIDE - Enhanced IDE. An improved parallel disk interface. Now being replaced by SATA, a serial interface.

EOT - End Of Thread (meaning end of discussion).

EPROM - Electronically Programmable Read-Only Memory - A type of memory used for permanent storage of small amounts of data.

ESF - Exchange Service Facility - BT term.

Ethernet - Method of transfering data in a LAN (Local Area Network). Special IP addresses are reserved for LAN routing (eg 192.168.0.0 - 192.168.255.255)

EU - End User. - BT and ISP term to describe the likes of you and me.

EULA - End User Licence Agreement.

EXE - Executable file type used in Windows.

[roseway]

FAT - File Allocation Table. A file system used in DOS and early versions of Windows. Still widely used in its FAT32 version for USB flash drives and for disk partitions which are to be shared with other operating systems.

FAQ - Frequently Asked Questions.

FDD - Floppy Disk Drive.

FEC - Forward Error Correction. A method of transmitting data with extra information included, which can be used at the receiving end to correct errors which have occurred in transmission. This can speed up transmission over lines which are subject to errors, by avoiding the need to frequently retransmit packets of data. See ADSL Error Correction.

Femtocell - Mobile Cellular base station that allows mobile phone coverage over the broadband network.

FJ - Faults Jointer (BT Term).

FMPF - Full Metallic Path Facility.  Type of LLU provision where both the voice line and adsl is provisioned by a Telco other than BT.  Also known as Fully Unbundled.

FNF - Fault Not Found (BT Term). When a condition or a reported problem has been verified by a Test System OR directly observed by BT people and subsequently the cause of the condition or problem cannot be found.

FT - Field Terminal (BT)

FTP - First Terminating Point (BT)

FTP - File Transfer Protocol.  A  method of transferring data and files over a network or the Internet.

FTTC, FTTH, FTTP - Fibre To The Cabinet, Fibre To The Home, Fibre To The Premises. The use of high-speed fibre optic cable to connect part or all of the way from the exchange to the user.

[roseway]

Gb - Gigabit. 1000 or 1024 megabits.

GB - Gigabyte. 1000 or 1024 megabytes.

GDI - Graphics Device Interface. The graphics part of Windows.

GIF - Graphics Interface Format. A commonly used format for storing bitmapped graphics. GIF only supports up to 256 colours, so is not suitable for photographs. But it supports animation, so is very useful for small moving pictures (such as forum smilies).

GPON - Gigabit Passive Optical Network.

GPU - Graphics Processing Unit. Commonly referred to as the graphics card in a PC, but is often incorporated into the motherboard.

GUI - Graphical User Interface. The familiar operating system interface which uses a graphical display and can be operated by various input devices such as keyboard, mouse, trackball, etc.

[roseway]

HAL - Hardware Abstraction Layer. The part of an operating system which interfaces with the hardware.

HDD - Hard Disk Drive.

HEC - Header Error Control/Correction - More info Error correction - HEC

HF - High Frequency.

HR Fault - High Resistance / High Open Fault.  Usually caused by corroded joint or cable.  See ~ adsl only works when the phone is being used for more info.

HTML - HyperText Markup Language. The original (and still used) language of websites.

HTTP - HyperText Transfer Protocol. The protocol which is used for connecting sites on the World Wide Web (WWW).

Hz - Hertz. A measure of frequency, equal to cycles per second.

[roseway]

i18n - Internationalisation (the first and last letters of the word, with 18 letters in between).

IANAE - I Am Not An Expert.

IANAL - I Am Not A Lawyer.

IBM - International Business Machines. One of the largest and most influential computing companies in the world.

IC - Integrated circuit ('silicon chip').

ICB - Incoming Calls Barred (BT).

ICD - Internal Cable Distribution. (BT)

ICMP - Internet Control Message Protocol. One of the core internet protocols, mainly used in networks to send error messages, but also used by ping and traceroute / tracert.

IDC - Insulation Displacement Connector

IDE - Integrated Development Environment. An 'everything in one place' environment for software development.

IDE - Integrated Drive Electronics. Hardware included in disk drives to standardise the interface to the computer.

IE - Internet Explorer. Microsoft's browser, which is included with Windows.

IM - Instant Messaging. A real-time medium for exchanging text messages over a network.

IMHO - In My Honest Opinion

IMHO - In My Humble Opinion

IP - Internet Protocol. One of the original core protocols of the internet, often combined with TCP as TCP/IP.

IP Address - Internet Protocol Address. The address of an internet or local network site in numerical form (e.g. 192.168.1.254).

IP Profile - A BT Wholesale configuration setting for ADSL Max, closely related to the bRAS profile. It is set automatically according to the user's lowest recent connection speed, and defines the maximum download speed which can be achieved on that connection. See IP / bRAS Profile.

IP Stream - Type of adsl where the ISP uses BT Wholesale's backhaul and equipment at the exchange. - See IPStream for more info on how it works.

IRC - Internet Relay Chat. A real-time medium for exchanging text messages over a network, mainly used in group discussion forums called channels.

IRQ - Interrupt Request. A computer hardware system which allows programs and hardware devices to interrupt the CPU and get some attention.

ISA - Industry Standard Architecture. An interface design for plug-in cards in a computer, now mainly obsolete.

ISDN - Integrated Services Digital Network. A digital telephone connection system allowing simultaneous transmission of speech and data. Now largely superseded by DSL broadband.

ISP - Internet Service Provider. The provider of internet services to the end user.

IT - Information Technology. An umbrella term for anything to do with computers and related subjects.

[kitz]

JPEG - Joint Photographic Experts Group. File type for digital images.

JRE - Java Runtime Environment.

JVM - Java Virtual Machine.

[kitz]

kb - Kilobit (1024 bits)

kB - Kilobyte (1024 bytes)

kbps - Kilobits per second

kBps - KiloBytes per Second, may also be denoted as KB/Sec

kHz - Kilohertz, a measure of frequency. 1 kHz = 1000 cycles per second.

[kitz]

L2TP - Layer Two Tunnelling Protocol.  A protocol that enables Virtual Private Networks.  L2TP is used by BTw for IP Stream ISPs to hide the BTw part of the network, so that the first hop a user will see will be the ISPs home gateway.

LAN - Local Area Network.

LCD - Liquid Crystal Display.

LEN - Line Equipment Number (BT)

Line Rate - The speed at which you connect (synchronise) to the exchange.

Line Stats - Statistics obtained from your router which gives information about the condition of your line and adsl connection.
                    How to get your line stats.  How to interpret your line stats. A brief explanation of your line stat figures.

LJU - Line Jack Unit. - See BT sockets and Line Jack Units for more info and help identifying your LJU.

Local Loop - The telephone cabling network between the exchange and the customer premises.

LLU - Local Loop Unbundling.  When another telecoms provider or ISP installs their own equipment in the BT exchange and makes alternative arrangements for back haul provision.  There are 2 types of LLU - FMPF (or MPF) and SMPF.

LLUMS - Local Loop Unbundling Management System. An Openreach system primarily used to monitor and report on the status of each cabinet  DSLAM. It is also used to monitor the FTTC service take-up and trigger the addition of further line cards to the DSLAM.

LOL - Laughing Out Loud.

LTS - L2TP Tunnel Switch.  Also known as the ISP home gateway.  More info here

[roseway]

MAC - Migration Access Code. A number which you obtain from your present ISP in order to migrate to a different ISP, without having to cancel and re-order.

MAC address - Media Access Control Address. A unique serial number which is assigned to a network adaptor to enable correct routing of data packets in a network.

Mb - Megabit. 1024 kilobits (kb).

MB - Megabyte, 1024 kilobytes (kB).

Mbps - Megabits per second (also written as Mb/sec).

MBps - Megabytes per second (also written as MB/sec).

MBR - Master Boot Record. The first 512 bytes on a disk, which are reserved for booting the machine.

MDF - Main Distribution Frame.  The point at which the copper pair terminates at the telephone exchange.  - See Inside the telephone exchange

MF - Medium Frequency.

MHz - Megahertz, a measure of frequency. 1 MHz = 1 million cycles per second.

MPEG - Motion Pictures Expert Group. A file type for moving pictures.

MS - Microsoft.

MSAN - Multi Service Access Node.  Next Generation DSLAM which can support multiple transport technologies. More info MSAN.

MTU - Maximum Transmission Unit. MTU and RWIN

[roseway]

NAS - Network Attached Storage. A data storage device which is connected to a network.

NAT - Network Address Translation. The process of changing the IP address in data packet headers passing through a network routing device, so as to remap one address space into another. Commonly used in domestic and office routers to provide a separation between the internal (LAN) addresses and the external publicly visible internet address. See Network Address Translation.

NIC - Network Interface Card / Controller. A piece of hardware which enables a computer to connect with a network, usually built into the motherboard of modern machines.

NNTP - Network News Transfer Protocol. The protocol which is used for transferring news articles in Usenet, and also for transferring news between servers.

NOC - Network Operations Centre.

NTE - Network Terminating Equipment. 

NTE5 - Network Terminating Equipment. The BT Master Socket

NTFS - New Technology File System. The file system which is used in all recent versions of Windows.

NTP - Network Time Protocol. A protocol for synchronising computer clocks over networks. A world-wide network of NTP servers are synchronised to highly accurate time sources, and computers can connect to these servers to maintain the accuracy of their own clocks.

NTP - Network Terminating Point.

NTTP - Network Terminating and Test Point (BT)

NTU - Network Terminating Unit.

NVRAM - Non Volatile Random Access Memory. A generic term for memory which does not lose its data when the power is disconnected.